Temperature compensated latching ferrite phase shifter

ABSTRACT

A nonreciprocal latching phase shifter that is compensated for changes in temperature. A pair of ferrite rectangular toroids in series connection are inserted into a rectangular waveguide and a dielectric material is inserted within the toroids with a magnetizing wire centrally disposed within the dielectric material and connected to a source of magnetizing current outside the waveguide. The ferrite material of one of the pairs of toroids has a remanent magnetization that increases with increasing temperature while the other of the pair has a remanent magnetization that decreases with increasing temperature.

United States Patent [191 Bardash et al.

TEMPERATURE COMPENSATED LATCHING FERRITE PHASE 'SHIFTER Inventors: Irwin Bardash, Stony Brook;

Christian Schlotterhausen, Commack, both of N.Y.

The United States of America as represented by the Secretary of the Air Force, Washington, DC.

Filed: Apr, 11, 1973 Appl. No.: 350,257

Assignee:

US. Cl. 333/24.1, 333/83 T Int. Cl. H0 lp 1/32 Field of Search 333/24 G, 24.1, 24.2, 82 BT,

References Cited UNITED STATES PATENTS 9/1966 Chiron 333/241 FE/QE/ TE W/n/ 6500/1/0 7244, 564 rues July 16, 1974 6/1969 Andrikian 333/24.l X 5/1973 Smith 333/24.]

Primary Examiner-Paul L. Gensler Attorney, Agent, or Firm-Harry A. Herbert, Jr.; Julian L. Siegel [57] ABSTRACT A nonreciprocal latching phase shifter that is compensated for changes in temperature. A pair of ferrite rectangular toroids in series connection are inserted into a rectangular waveguide and a dielectric material is inserted within the toroids with a magnetizing wire centrally disposed within the dielectric material and connected to a source of magnetizing current outside the waveguide. The ferrite material of one of the pairs of toroids has a remanent magnetization that increases with increasing temperature while the other of the pair has a remanent magnetization that decreases with increasing temperature.

4 Claims, 6 Drawing Figures TEMPERATURE COMPENSATED L'ATCHING FERRITE PHASE SHIFTER BACKGROUND OF THE INVENTION This invention relates to phase shifters, and more particularly to a temperature compensated nonreciprocal digital latching ferrite phase shifter.

The nonreciprocal digital latching ferrite phase shifter is the most common phasor device used in phased array antenna systems. Unfortunately its differential phase shift characteristics are extremely temperature sensitive. This sensitivity is caused by the fact that the magnetic properties of the internal ferrite toroids are temperature dependent. The temperature compensated nonreciprocal digital latching ferrite phase shifter overcomes this temperature sensitivity. I

This temperature compensating system is applicable to toroids fabricated out of microwave garnets as well as microwave ferrites. It may be applied not only to phase shifter devices in phased array antenna systems but to four port switchable ferrite circulators because they contain ferrite toroid sections. In order to achieve good circulator performance, i.e., high isolation and low insertion loss, over wide temperature ranges, the temperature compensated nonreciprocal digital latching ferrite phaseshifter may be used.

SUMMARY OF THE INVENTION The present invention is a ferrite nonreciprocal phase shifter temperature compensated to overcome sensitivities of conventional ferrite materials which undesirably affect the ferrite magnetic properties. The invention includes a digital latching ferrite toroid made up of two ferrite toroids positioned in tandem. Temperature compensation is achieved by making one of the two toroids in tandem out of a material whose remanent magnetization decreases with increasing temperature and the other of the two toroids in tandem out of a material whose remanent magnetization increases with increasing temperature. The relative lengths of the toroids are adjusted to yield optimally flat differential phase shifts as a function of temperature.

It is therefore an object of the invention to provide a novel and improved nonreciprocal digital latching ferrite phase shifter.

It is another object to provide a latching ferrite phase shifter that is independent of changes in temperature.

It is still another object to provide a temperature independent nonreciprocal digital latching phase shifter that can be used with propagating structures such as coaxial lines, wave-guides, striplines, and H-guides.

These and other objects, advantages and features of the invention will become more apparent from the following description taken in connection with the illustrative embodiment in the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram of a single ferrite bit of a conventional digital latching ferrite phase shifter;

FIG. 2 is a cross section of the conventional digital latching phase shifter showing the ferrite toroid taken at 22 of FIG. 1;

FIG. 3 is a graph of the 8-H characteristics of a typi-- cal microwave ferrite;

.exhibit positive temperature characteristics; and

FlG.6 is a diagram of the temperature compensated nonreciprocal digital latching ferrite phase shifter which is an embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referringto FIG. 1, there is shown a single ferrite bit of a conventional digital'latching ferrite phaseshifter.

It consists of'ferrite toroid l1, magnetizing wire 13 inserted through the ferrite material matching transformer sections 15 and 17 at each extreme of toroid l1 and waveguide propagating structure 19 in which toroid 11 is mounted. In the present embodiment a waveguide is illustrated; however, the principle of the invention is applicable to phase shifters constructed in all of the other electromagnetic propagating structures such as coaxial line,stripline, I-l-guide, etc.

FIG. 2 is a cross-sectional view of ferrite portion 11 and shows that it has the shape of aclosed toroid and is loaded with dielectric insert 21 which centrally locates magnetizing wire 13 in the device and also en'- hances the phase shift produced by the device.

FIG. 3 shows the B-H loop of a typical microwave ferrite used in fabricating toroids for digital phase shifters. The differential phase shift produced by a single digital bit (as illustrated in FIG. 1). is directly proportional to the distance between the remanent magnetizations, -B, and -l-B,. Thephase shifter is phased by applying current pulses to magnetizing wire 13. A current pulse that produces a magnetomotive force, greater than the coercive force of the material willsaturate-the toroid. When the pulse is removed, the remanent magnetic flux, 8,, remains in the toroid. For negative current pulses of the same magnitude, 'B, .will be latched" into the toroid. If the values B, and +8, vary with temperature, then the differential phase associated with the distance between B, and +8, will vary.

FIG. 4 is-a plot of +3, (or -B,) as a function of temperature for a typical microwave ferrite material in which the remanent magnetization decreases with increasing temperature. A digital latching device constructed with this type of material would produce decreasing phase shift with increasing temperature. FIG. 5 is aplot of +3, (or -B,) as a function of temperature for ferrite materials that have increasing remanent magnetizations with increasing temperatures. A digital latching device constructed with this type of material would produce increasing phase shift with increasing temperature.

FIG. 6 is a drawing of a temperature compensated nonreciprocal digital latching ferrite. phase shifter I which is the subject of .the present invention. It contains two ferrite toroids in series and abutting. Toroid 23 is fabricated out of-a ferrite material that has negative B versus temperature characteristics and toroid 25 is fab ricated out of a ferrite material that has positive B, versus temperature characteristics. These ferrites can be polycrystalline yttrium-iron-gamet and doped toobtain the proper B, vs. temperature characteristics. For a negativecharacteristic the doping material can be phase shift as a function of temperature.

what is claimed is: l. A temperature compensated latching digital phase shifter comprising: a. an electromagnetic propagating structure; b. first and second gyromagnetic toroids disposed within the electromagnetic propagating structure 4 in series connection and with the material of the first toroid having an increasing remanent magnetization with increasing temperature and the material of the second toroid having a decreasing magnetization with increasing temperature; c. a dielectric material inserted within the first and second toroids; and d. a magnetizing wire passing through the dielectric material. 2. A latching digital phase shifter according to claim 1 wherein the toroid material is ferrite.

3. A latching digital phase shifter according to claim 1 wherein the toroid material isgarnet.

4. A latching digital phase shifter according to claim 2 wherein the electromagnetic propagating structure is a rectangular waveguide and the ferrite material is a rectangular toroid. 

1. A temperature compensated latching digital phase shifter comprising: a. an electromagnetic propagating structure; b. first and second gyromagnetic toroids disposed within the electromagnetic propagating structure in series connection and with the material of the first toroid having an increasing remanent magnetization with increasing temperature and the material of the second toroid having a decreasing magnetization with increasing temperature; c. a dielectric material inserted within the first and second toroids; and d. a magnetizing wire passing through the dielectric material.
 2. A latching digital phase shifter according to claim 1 wherein the toroid material is ferrite.
 3. A latching digital phase shifter according to claim 1 wherein the toroid material is garnet.
 4. A latching digital phase shifter according to claim 2 wherein the electromagnetic propagating structure is a rectangular waveguide and the ferrite material is a rectangular toroid. 